Long lines, some over an hour, greeted attendees trying to enter Civic Center for the annual 4/20 cannabis celebration, and rain, mostly in the form of a steady drizzle, didn’t dampen the enthusiasm of most participants.

The park was packed with thousands as the annual countdown, Denver’s version of Times Square on New Year’s, ticked down and just about everyone in the crowd toked at the strike of one.

“I just love everyone can get together and legally enjoy marijuana,” said Noah Nellessen, 22, of Denver. “It doesn’t hurt anyone.”

Colorado law, however, prohibits smoking of marijuana in public. On Thursday, at 4:20 p.m., as well as before and after, waves of smoke billowed throughout the park.

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Civic Center was fenced off, with police vehicles parked in various spots and lots of officers checking on the fence perimeter from inside looking out.

At one long security line, on the north side of Civic Center, the pace was excruciatingly slow. Security staffers waved wands over people entering, checked bags and did pat-downs on some.

“It’s as long as hell,” said Luis Lara, 21, of Denver, as he queued up behind hundreds in front of him. “Why is there a line to get in anyway?”

One man, who tired of standing in the line as it drizzled rain, bolted. “I’m going to Aurora,” he announced, to little reaction.

One couple, a man and woman, cut in line on the sly. Most people were patient but antsy about getting in by the stroke of 4:20 p.m.

An electric highway sign, set up in front of the Wellington Webb Building, just off 15th Street, flashed the message: “Public Consumption of Cannabis is Prohibited.”

About 4:05 p.m., some people pulled down a long section of fence near the corner of Colfax Avenue and Broadway. Dozens rushed to the spot, running over the downed fence. One person shouted: “This is our freedom.”

A brief gunfire incident occurred early Thursday evening near the event in downtown Denver. Police said nobody was hurt.

About two hours later, at 6 p.m., at least one shot of gunfire was heard a block away, near 15th and Cleveland. Technician Tyrone Campbell, a Denver police spokesman, said witnesses gave officers a description of the people involved and the vehicle they had gotten into as they left the area.

Police quickly found the vehicle, Campbell said, and arrested two people. He did not have any information about the suspects, and he did not know whether they had been attending the 4/20 event.

“We’re going to investigate and see if there was any targeted activity,” he said. “Right now, we’re just happy to have two people in custody.”

In all, five people were arrested at the Civic Center event and 20 people were written up with civil citations, police said.

Inside the park it was a party atmosphere with music blasting and people dancing in a steady drizzle. Colorful umbrellas, plastic ponchos, dogs on leashes, cellphone photos and video opportunities were abundant.

Numerous vendors inside tents sold an assortment of items, including glass pipes, clothing and marijuana art. Food vendors in trucks lined West 14th Avenue, just north of the Denver Art Museum and the Denver Public Library, cooking an array of food. Trash littered sections of the park lawn.